12 Safe Fonts - defined on both PC & Mac

• arial
• arial black
• comic sans ms
• courier
• courier new
• georgia
• helvetica
• impact
• palatino
• times new roman
• trebuchet ms
• verdana

w/Bold

• arial
• arial black
• comic sans ms
• courier
• courier new
• georgia
• helvetica
• impact
• palatino
• times new roman
• trebuchet ms
• verdana

See also A Comprehensive Font-Example site